Here, ‘magnetic object’ refers to an object comprising components or parts made of a magnetic material. A magnetic material is a material which has magnetic properties measurable by an automatic magnetic object recognition apparatus.
‘Mobile’ refers to an object that can be moved. Thus, the mobile magnetic object is not always presented in the same position in front of the recognition apparatus. But the magnetic field measured by each magnetometer in the array depends on the position and orientation of the magnetic object presented. Thus, it is very difficult to reliably recognize the magnetic signature of a mobile magnetic object. Until now this problem has been circumvented, e.g. by attaching RFID (Radio Frequency Identification) tags on the magnetic object or by imposing a displacement of the magnetic object along a predetermined path so that it can be recognized.
The prior art is also known from GB2310930A, U.S. Pat. No. 7,932,718B1, U.S. Pat. No. 6,263,230B1, US2007/276218A1, U.S. Pat. No. 5,444,669A, U.S. Pat. No. 5,337,259A and U.S. Pat. No. 5,831,873A.